scholarly journals Effects of the Duration of 24-hr Photoperiodic Treatment and Gibberellin or Uniconazole Application on Inflorescence Formation in Turnip Plants

2004 ◽  
Vol 3 (1) ◽  
pp. 79-83 ◽  
Author(s):  
Hideyuki Saito ◽  
Takashi Saito
Keyword(s):  
Photoperiodic Treatment

Vegetative Activity of the Main Stem Terminal Bud Under Photoperiod and Flower Removal Treatments in Soybean

1988 ◽  
Vol 15 (3) ◽  
pp. 475 ◽  
Author(s):  
SV Caffaro ◽  
F Nakayama
Keyword(s):  
Main Stem ◽  
Internode Elongation ◽  
Apical Bud ◽  
Apical Buds ◽  
Long Day ◽  
Flower Abortion ◽  
Terminal Bud ◽  
Photoperiodic Treatment ◽  
The Moment ◽  
Short Days

Effects of photoperiod and flower removal on vegetative activity of the main stem apical bud were examined for an indeterminate ('Williams') and a determinate ('Bragg') soybean cultivar. Plants grew under long day conditions until the V2 stage. Then, they were subjected to three photoperiodic treatments: (1) short days of 9 h of solar radiation during all the experiment (SD); (2) 10 short days followed by long days until the end of the experiment (SD + LD); and (3) long days during all the experiment (LD). From the moment anthesis was reached, half of the plants of each photoperiodic treatment were periodically deflowered. Flower removal induced an additional but limited vegetative growth of the main stem apex, due to the elongation of the youngest internodes. This effect was only seen under SD because long day applications (SD+LD and LD) induced a high flower abortion. On the contrary, long days stimulated internode elongation, leaf expansion and, under LD, delayed anthesis which resulted in enhanced vegetative activity of apical buds and a greater production of nodes and branches. Thus, a close but inverse relation was observed between flower induction and vegetative structure differentiation by apical buds. As in Bragg, Williams may stop vegetative activity of buds by their simple transition to a terminal raceme hence, only posterior differentiated internode elongation will be either limited or stimulated depending on SD or LD conditions, respectively.

scholarly journals 391 THE INFLUENCE OF COLD DURING SEEDLING STAGE AND PHOTOPERIOD ON FORCING PERENNIALS FOR POT PLANTS

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 487b-487
Author(s):  
Allan M. Armitage ◽  
Paul Thomas
Keyword(s):  
Plant Height ◽  
Early Spring ◽  
Seedling Stage ◽  
Internode Elongation ◽  
Perennial Species ◽  
Photoperiodic Treatment ◽  
Short Days ◽  
Pot Plants

The influence of cooling, photoperiod and chemical branching on early spring flowering of perennial species was studied. Cooling was provided while plants were in plugs (128 plugs per tray) and dikegulac-sodium, a compound found to induce breaks in other species, was applied prior to, during and after cooling. Plants were cooled in insulated lighted coolers for 4, 8 or 12 weeks at 4C, and brought to a greenhouse with night temperatures between 8-12C. Long and short days were provided in the greenhouse after plants came out of the coolers. Little response to dikegulac occurred, however, Campanula, Sedum, Leontopodium, Catananche, Aubrietia, Arabis, Gypsophila, Anchusa and Aquilegia responded to cooling and photoperiodic treatment. Flowering and vegetative characteristics such as internode elongation and plant height responded to photoperiod and cooling but not all genera responded similarly. Anchusa, Campanula, Aquilegia and Gypsophila flowered significantly earlier under LD compared to SD. Twelve weeks of cooling resulted in flowering of all genera, however, some genera were equally responsive to shorter cooling times.

scholarly journals Viability Influenced by Photoperiodic Treatment During Growth and Egg Production

1963 ◽  
Vol 42 (6) ◽  
pp. 1462-1463 ◽  
Author(s):  
H.S. Siegel ◽  
W.L. Beane
Keyword(s):  
Egg Production ◽  
Photoperiodic Treatment

Effects of Photoperiodic Treatment on Stomatal Movement

Nature ◽  
1952 ◽  
Vol 169 (4312) ◽  
pp. 1053-1054 ◽  
Author(s):  
W. W. SCHWABE
Keyword(s):  
Stomatal Movement ◽  
Photoperiodic Treatment

scholarly journals Cyclical DNA Methyltransferase 3a Expression Is a Seasonal and Estrus Timer in Reproductive Tissues

Endocrinology ◽  
2016 ◽  
Vol 157 (6) ◽  
pp. 2469-2478 ◽  
Author(s):  
Eloise W. J. Lynch ◽  
Chris S. Coyle ◽  
Marlene Lorgen ◽  
Ewan M. Campbell ◽  
Alan S. Bowman ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Time Scales ◽  
Dna Methyltransferase ◽  
Reproductive Function ◽  
Multiple Time Scales ◽  
Multiple Time ◽  
Hormone Regulation ◽  
Photoperiodic Treatment ◽  
Dna Methyltransferase 3A ◽  
Dnmt3b Expression

It is becoming clear that epigenetic modifications such as DNA methylation can be dynamic and, in many cases, reversible. Here we investigated the photoperiod and hormone regulation of DNA methylation in testes, ovaries, and uterine tissue across multiple time scales. We hypothesized that DNA methyltransferase 3a (dnmt3a) is driven by photoperiodic treatment and exhibits natural variation across the female reproductive cycle and that melatonin increases whereas estrogen reduces DNA methylation. We used Siberian hamsters (Phodopus sungorus) due to their robust changes in reproductive physiology across seasonal and estrus time scales. Our findings indicate that short-day (SD) winter-like conditions significantly increased global DNA methylation and dnmt3a expression in the testes. Using immunohistochemistry, we confirm that increased dnmt3a expression was primarily localized to spermatogonium. Conversely, the ovaries did not exhibit variation in DNA methylation or dnmt3a/3b expression. However, exposure to SD significantly increased uterine dnmt3a expression. We then determined that dnmt3a was significantly decreased during the estrus stage. Next, we ovariectomized females and subsequently identified that a single estrogen+progesterone injection was sufficient to rapidly inhibit dnmt3a and dnmt3b expression. Finally, we demonstrate that treatment of human embryonic kidney-293 cells with melatonin significantly increased both dnmt3a and dnmt3b expression, suggesting that long-duration nocturnal signaling in SD may be involved in the regulation of DNA methylation in both sexes. Overall, our data indicate that dnmt3a shows marked photoperiod and estrus plasticity that likely has broad downstream effects on the timing of the genomic control of reproductive function.

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